KR101167325B1 - A fluid pump controlling system, a fluid pump controlling method, a linear compressor and a cooler - Google Patents

Abstract

The present invention relates to a cooler and a linear compressor equipped with means for metering each operation on first use or in case of problems caused by electrical or mechanical errors, as well as a method and system for controlling the fluid pump 10. According to the present disclosure, the fluid pump 10 is provided with a piston-position sensing assembly 11, wherein the electronic controller 16 monitors the piston displacement in each cylinder by detecting an impact signal. The impact signal is transmitted by the sensing assembly 11 upon the occurrence of an impact with the stroke end of the piston and the electronic controller 16 triggers as far as the occurrence of the impact to store the maximum value of the piston displacement. The piston displacement stroke is continuously increased when there is a signal.

Description

Fluid Pump Control System, Fluid Pump Control Method, Linear Compressor and Cooler {A FLUID PUMP CONTROLLING SYSTEM, A FLUID PUMP CONTROLLING METHOD, A LINEAR COMPRESSOR AND A COOLER}

This application claims the priority of the Brazilian patent application PI0305458-6 of December 5, 2003, which is hereby incorporated by reference.

The present invention not only relates to a method and system for controlling a fluid pump, but also to provide for the use of such equipment to calibrate each function in the event of problems due to electrical or mechanical disturbances or at the time of first use. A cooler and a linear compressor are provided.

Fluid pumps, such as linear compressors, are typically controlled by an electronic controller, which regulates the voltage supplied to the electric motor that drives the piston in the cylinder into which the gas or liquid is compressed.

For example, in the case where a valve plate of a linear compressor is found, a piston having a stroke moving up to the stroke end is positioned displaceably in the cylinder.

One of the problems found within this type of equipment is the fact that the piston can impact (or crash) with the stroke end, cause noise or even destroy the equipment. Thus, it is necessary to control the position of the piston as well as the occurrence of a collision with each stroke end.

Typically, conventional systems foresee the monitoring of a collision while using a fluid pump to avoid the problems mentioned above.

In addition, in order to achieve the maximum capacity or maximum efficiency of the fluid pump, the pump piston must reach the maximum possible position. As the piston operates very close to each stroke end, it is necessary to use a displacement sensor with good accuracy in order for the system to operate safely in these conditions, and it is also essential to meter the system, which is necessary to It can be hard.

For sensors with low accuracy, it is essential to reduce the maximum possible displacement of the piston. In this way, the piston will operate at a greater distance from the stroke end, thereby increasing the stability of the fluid pump, but at the expense of maximum capacity and respective efficiency.

Another problem relates to gain and offset loss. The problem is particularly relevant because, in addition to the stroke, for example, by using an accelerometer type sensor, there are other factors affecting acceleration, for example the discharge and suction pressure of the fluid pump. This is because as these factors change during operation, the response of the sensor will also change.

In certain types of sensors, for example, where it is necessary to meter a fluid pump, there may be the effect of changes in temperature that make them unsuitable for measurement.

Technically, the sensor can generally be approximated by the following formula.

Y = m × X + b

Where Y is the stroke (output signal of the sensor);

X is the measured physical size (inlet of the sensor);

m is a gain or multiplicative element; And

b is the offset or additional element.

Based on this equation, it can be seen that if the elements m and b change depending on the type of sensor (eg some change in temperature, pressure), the response of the sensor will change.

Although previous techniques provide control regarding the positioning of pistons and the occurrence of collisions, nothing predicts the necessary calibration to enable the control system to be employed on a large scale in the manufacture of fluid pumps.

The problem is that the electrical and mechanical components used in the manufacture of the fluid pump generally have several levels of tolerance, so that the fluid pump has little or no properties identical to one of the other pumps manufactured by the same specification. Because of the fact that it does not have.

The result is that when manufacturing a fluid pump with a system for monitoring the position and impact of the piston, as mentioned above, the final adjustment is made to each piece of equipment, and in this way, from the tolerances of the parts In order to eliminate possible inaccuracies caused, it will always be necessary to foresee the metering step during assembly or manufacture of the fluid pump.

Clearly, the need to employ additional weighing steps in a manufacturing or assembly line results in significant time losses, resulting in financial losses.

One of the methods of controlling the movement of the piston in the compressor is described in US Pat. No. 6,536,326. According to this previous description, monitoring of piston collisions, for example by a microphone, is foreseen. When an impact occurs, a fault signal is generated and fed to the electronic control circuit to drive with respect to the piston displacement, thereby preventing further collisions. The system also predicts the storage of the maximum value of the piston displacement from the occurrence of the collision.

In order to prevent the occurrence of a collision, according to the presentation of the document US 6,536,326, it is not possible to adjust the maximum value of the piston displacement, so the above steps and metering in the manufacturing and assembly line continue to be essential.
Another prior art reference US 6,176,683 discloses monitoring of piston collisions in a compressor. According to this document, when a collision is detected, the system considers the collision an abnormal situation, after which the piston stroke is corrected. However, this solution does not avoid metering the piston stroke during assembly of the compressor.
According to another prior art reference US 2003/0161734, an apparatus is disclosed. The apparatus has a current detecting unit for detecting a current, a control unit for determining whether a collision has occurred between the piston and the valve, and controlling the stroke of the linear compressor. This technique also, while assembling the compressor, does not foresee a solution that avoids metering the piston stroke.
Furthermore, according to another prior art reference US 2003/0219341, a reciprocating machine is disclosed. According to the document, a variable voltage driver is provided for driving the piston, and a vibration sensor is provided for detecting the contact between the piston and the cylinder end. In order to maximize the piston stroke and reduce the contact between the piston and the cylinder if not eliminated, a controller is provided which connects the sensor and the actuator to each other to control the movement of the actuator and the piston. This solution also avoids metering the piston stroke during assembly of the compressor.

The present invention preferably informs the occurrence of a mechanical impact of the piston (or foresee a mechanical impact or collision) at the end of the stroke and an output informing the maximum piston displacement in the fluid pump, preferably processing a signal from the displacement sensor. A pump and method for controlling a fluid pump, as well as a cooler and a linear compressor with control with electronic circuits, having different outputs. The control also predicts a metering method / algorithm that can adjust the maximum limit of piston displacement with information from the circuitry that processes the signal from the displacement sensor.

The weighing method may be performed each time the system is turned on or whenever a failure occurs. In addition, periodic metering can be established at a predetermined time, which is determined by the characteristics of the sensor being used.

Moreover, in order to have the maximum efficiency of the fluid pump, the piston should be operated as close to the stroke end as possible. The ideal value would be for operating where the distance from the end of the stroke is zero, but the method and system according to the invention are self-weighing because it is impossible due to vibration or tolerance errors in the piston stroke. It allows you to eliminate the cause of the error from self-calibration, allowing it to be as close as possible to the end of the stroke. If this is not possible and the piston needs to be operated at greater distances from the stroke end, the compressor will be used under full capacity. Along with this, the safety distance of the piston from the stroke end corresponds to a volume called a "dead volume" in which a portion of the gas stored in the dead volume is compressed and decompressed during operation of the compressor, causing loss. . The ideal situation is that the entire gas is pumped and no stored gas remains in the dead volume.

The present invention is as follows:

The piston proceeds as far as the end of its mechanical stroke, controlling the piston stroke in the fluid pump, not allowing the collision of the piston on the cylinder top, and without reducing the dead volume value in the cylinder to a minimum. Allow,

Avoiding the weighing procedure during the manufacturing or assembly process, and implementing an automatic metering system during normal operation of the fluid pump that can operate the piston at the shortest possible distance from each stroke,

Enabling the use of less accurate or less accurate sensors without losing the performance (efficiency and maximum capacity) of the system,

-Optimize the fluid pump in efficiency and capacity,

It aims to carry out simple solutions for large scale industrial production.

The objects of the present invention are achieved by a fluid pump control system, the fluid pump comprising a piston repositionably positioned in a cylinder, the cylinder having a piston displacement stroke, the cylinder having a stroke Having a stroke end, the fluid pump is driven by a voltage-driven electric motor, the system includes an electronic controller for controlling the voltage, the system sensing the piston measuring the behavior of the piston An electronic controller electrically connected to the assembly and the sensing assembly, wherein the electronic controller is arranged to monitor piston displacement in the cylinder by detecting an impact signal, wherein the impact signal is generated when the impact occurs at the stroke end of the piston. Delivered by the sensing assembly, An impact signal is transmitted by the sensing assembly to the electronic controller, the electronic controller configured to continuously increase the piston displacement stroke by increasing the voltage supplied to the electric motor, wherein the voltage increase is a stroke. Commanded by the trigger signal until the occurrence of the impact to store the maximum value of the piston displacement corresponding to the piston displacement by the end.

The object of the invention is also achieved by a method of controlling a fluid pump comprising a piston repositionably positioned in a cylinder, the cylinder having a piston displacement stroke, the cylinder having a stroke end, and the method Turning on the fluid pump to cause the piston to move within the cylinder; Continuously increasing the piston stroke to the extent that a collision with the stroke end occurs, and monitoring the piston stroke for a stabilization time between successive increases in the stroke; And when the impact occurs during the stabilization time, reducing the piston stroke.

Furthermore, another way of carrying out the subject matter of the present invention is to provide a control system for controlling a fluid pump including a sensing assembly for sensing piston position and an electronic controller electrically connected to the sensing assembly. The electronic controller monitors the piston displacement in the cylinder by detecting an impact signal, the impact signal being transmitted by the sensing assembly upon the occurrence of a collision at the stroke end of the piston, the impact signal being the sensing assembly. Is transmitted to the electronic controller, the electronic controller continuously increasing the piston displacement stroke until the occurrence of the collision from a trigger signal to store the maximum value of the piston displacement, and the piston displacement in the cylinder. To prevent displacement by the maximum value of the piston displacement.

Another method of carrying out the teachings of the present invention comprises the steps of turning on a fluid pump to generate displacement of a piston in a cylinder; Continuously increasing the piston stroke until the impact at the stroke end occurs, monitoring the piston stroke during the stabilization time, and reducing the piston stroke if an impact occurs during the stabilization time. It is a way.

The objects of the present invention are further achieved by a linear compressor comprising a piston repositionably positioned in the cylinder. The cylinder has a piston-displacement stroke, the cylinder has a stroke end, and the system includes a sensing assembly that senses a piston position, and an electronic controller electrically connected to the sensing assembly, the electronic controller having an impact signal. Monitoring the displacement of the piston in the cylinder by detecting the impact signal is transmitted by the sensing assembly in the event of a collision between the piston and the stroke end, the impact signal is transmitted to the electronic controller by the sensing assembly, The electronic controller continuously increases the piston displacement stroke until a collision occurs to store the maximum value of the piston displacement.

Moreover, the objects of the invention are achieved by an ambient cooler comprising a control system for controlling the fluid pump. The fluid pump includes a piston repositionably positioned within a cylinder, the cylinder having a piston-displacement stroke, the cylinder having a stroke end, and the system electrically connected to a sensing assembly and the sensing assembly. A controller, wherein the electronic controller monitors piston displacement in the cylinder by detecting an impact signal, the impact signal being transmitted by the sensing assembly in the event of a collision at the stroke end of the piston, the impact signal being It is delivered by the sensing assembly to the electronic controller, which continuously increases the piston-displacement stroke from the trigger signal until the occurrence of the collision, in order to store the maximum value of the piston displacement.

The invention will be explained in more detail with reference to the embodiments shown in the following figures.

1 shows a block diagram of a system according to the invention.

2 shows a block diagram of a system according to the invention applied to the control of a linear compressor.

3a shows a block diagram of a system according to the invention using one sensor.

3b shows a block diagram of a system according to the invention using two sensors.

4 shows a detailed block diagram of the system of the present invention when one sensor is used.

5 shows an electrical circuit diagram of one of the methods for performing a second filter circuit.

6 shows an electrical circuit diagram of one of the methods for performing a first filter circuit.

7 shows a graph of the signal read into the sensing assembly of the present invention.

8 shows a flowchart of a self- weighing routine / method of the system of the present invention.

Figure 9 shows an average graph showing the situation in normal operation, made on a linear compressor provided with a system according to the invention.

Fig. 10 shows an average graph showing a situation in which there is an impact, made on a linear compressor provided with a system according to the present invention.

As can be seen in FIG. 1, the use of the system of the present invention on a cooling system in which a linear compressor 10 ′ is used is illustrated.

The teachings of the present invention can be employed with any type of fluid pump, which is particularly suitable in the case of linear compressors, since these equipments require strict metering to avoid problems while they are being used. to be.

The control system for controlling the fluid pump is typically controlled by an electronic controller 16, which is preferably supplied to an electric motor (not shown) that drives the fluid pump 10. And a microcontroller 15 for controlling the voltage.

The voltage supplied to the electric motor is controlled by the electronic controller 16 by controlling the conduction time of a set of switches 17 (preferably TRIACs) via a gate, and consequently, a fluid pump ( 10) movement is controlled. In the particular application shown in the figures, the capacity of the compressor 10 'is controlled so that the cooled environment 18 remains within the desired conditions.

The fluid pump 10 comprises a piston (not shown) repositionably positioned in the cylinder, the cylinder being stroke end, for example when the valve plate is located in the linear compressor 10 '. It has a piston displacement stroke of a distance.

In order for the system to operate under ideal conditions, the piston must move as close as possible to each stroke end, but there must be no collision at each stroke end, and not too far from the stroke end, in this case the efficiency of the pump. Because it is lower.

Structural Features at Fluid Pump 10:

Sensing  assembly

According to the present disclosure, a sensing assembly 11 having a position sensor 36 and an impact sensor 35 for detecting a piston displacement stroke should be provided.

The impact sensor 35 must be positioned to detect a collision at the stroke end of the piston and to generate an impact signal to the electronic controller 16.

One of the types of sensors that can be used in the system of the present invention is described in patent document BR0301969-1, filed May 22, 2003, which describes an accelerometer capable of detecting the impact of the piston against the stroke end. It is a sensor.

Other types of sensors can also be used, as long as it detects a crash or the urgency of a crash to prevent an impact signal to the electronic controller 16.

For example, the sensors described in BR0001404-4 and BR0200989-0 can be used. In both cases, impact sensors can generate an impact signal corresponding to a displacement or impact very close to the piston stroke end.

Sensor operation:

In order to implement the system of the invention, the piston must be operated by increasing its stroke until the impact is felt from the sensing assembly 11, in particular from the impact sensor 35.

When the piston hits the end of the stroke or touches the impact sensor 35, it can be recognized that the piston has reached the maximum displacement value, which can be stored in the electronic controller 16.

The system must be designed such that the maximum value of the piston displacement corresponds to the displacement of the maximum efficiency of the fluid pump 10 in order to at the same time have a minimum risk of proper efficiency of the pump and impact of the piston with the stroke end.

Since both the electronic components and the mechanical components used to make each fluid pump 10 have tolerances, each piece of equipment will have a different stroke end value and a different maximum displacement value, thus metering up to the impact point. Eliminate tolerances commonly found in this fluid pump.

This may be done every time the fluid pump 10 is started, with respect to the frequency at which the above procedures are applied, for example in the case of a cooler, each time the compressor 10 'is turned on. . While using the fluid pump 10, it may be chosen to carry out the procedure, for example, daily, with a frequency or determined frequency necessary to prevent impact problems. The metering can begin with the application of an external signal, eg foreseen for the start of the procedure whenever an electrical disturbance occurs in the network.

To implement this, the electronic controller 16 must generate a trigger signal when a problem with the fluid pump 10 occurs to initiate the metering procedure.

Preferably, starting from the trigger signal, i.e. in the event of a problem or when the motor is turned off, starts the fluid pump 10 with a minimum piston displacement stroke.

After metering, ie once the maximum value of the piston displacement is obtained, the value obtained in the electronic controller 16 must be stored. By monitoring the piston stroke, the piston stroke and its impact can be determined by accepting the maximum value obtained by metering of the system (or magnetic metering, since the system finds the maximum point for each fluid pump). The monitoring system must be operated at the same time.

The monitoring can be validated in various ways. For example, one may choose to monitor the piston position based on the presentation of patent BR9907432-0, the disclosure of which is incorporated herein by reference. Thus, in accordance with the teachings of the present invention, it should be foreseen to store the maximum value of the piston displacement in the cylinder of the fluid pump 10 and to evaluate whether the piston will collide, so that the electric motor driving the fluid pump 10 Reduce the voltage value supplied to the to prevent the piston from colliding.

Systems for monitoring the piston position described in these documents will have a maximum value of the piston displacement, which can be operated to prevent excessive piston displacement.

With simultaneous monitoring of piston stroke and impact, in addition to the greater efficiency of the fluid pump, greater stability in this operation is obtained. Specifically, the monitoring of the impact has two functions: the first function, during the metering procedure, to inform when the piston has reached the maximum limit of displacement and to adjust the piston stroke; The second function is to monitor the normal operation of the fluid pump to prevent impact from failures.

Sensing  Interpretation of the numerical value of assembly 11:

As can be seen in FIGS. 9 and 10, the piston movement in the cylinder shows a curve corresponding to the displacement measured by the position sensor 36 and the impact sensor 35.

9 illustrates a situation in which the piston operates without generating an impact. As can be observed, in this situation, the signal output from the position sensor 36 (curve 110) represents the maximum piston displacement in the absence of noise (see reference numeral 120). While curve 100 represents the signal of piston displacement after passing through filter circuit 42, curve 150 represents no impact of the piston because there is a measured signal.

10 illustrates a case in which the piston operates in conjunction with the occurrence of an impact. As can be observed, in this case, the output 110 'of the sensing assembly 11 generates noise (see reference numeral 120), which causes the signal 150' after the first filter circuit 40. Can be interpreted by the electronic controller 16 and even directly connected to one or the equivalent of the ports of the microcontroller 15. The curve 100 'is obtained after the second filter circuit 42 (low pass circuit) and represents a signal of piston displacement.

Sensing  System for measuring and interpreting the numerical values of assembly 11:

As can be seen in FIGS. 3A, 3B and 4, the signals from the sensing assembly 11 are interpreted by the signal processing modules 30 and 31, which can be performed in two structural ways. In other words:

By using one sensor:

Since the signal from the sensor can monitor the piston position and the piston impact, ie the movement of the piston at the same time, the low frequency signal (monitoring the piston position) and the high frequency so that the numerical values can be interpreted by the electronic controller 16. Separation of the signal (impact situation) should be foreseen.

For this purpose, the system of the present invention should be provided with a signal processing module 30 having a first filter circuit 40 and a second filter circuit 42.

For example, an inductive-type sensor can be selected. In this embodiment, the sensing assembly 11 will generate not only an impact signal but also a measurable wave of piston displacement upon collision with each stroke end of the piston. In this case, the signal processing module should be suitable for separating the signals generated by this type of sensor.

As can be seen in FIGS. 4 and 6, the first filter circuit 40 is a high pass filter. In this embodiment, the filter removes the signal read by the sensing assembly 11 at low frequency, i.e., the signal corresponding to the piston displacement, so that only the signal corresponding to the impact can pass to the electronic controller 16. Allow it.

The second filter circuit 42 is of low pass type in order to remove the high frequency from the signal read in the case of the piston impact. The signal read in this case will correspond to the signal of the piston displacement in the cylinder, which is transmitted to the electronic controller 16 and interpreted by the electronic controller.

6 illustrates one of the embodiments of the first filter circuit 40. In this embodiment, the assembly constituted by resistor R ₁₇ and capacitor C ₁₇ constitutes a high pass filter, for example to be configured to cut frequencies below 5 KHz when the present invention is employed in a linear compressor. do. Resistor R ₂₇ has a function of limiting the current delivered based on transistor 77 which amplifies the signal read by the sensing assembly 11.

5 illustrates one of the embodiments of the second filter circuit 42. In this embodiment, the assembly formed by resistor R ₄₆ and capacitor C ₄₆ operates as a high pass filter, while the assembly formed by capacitor C ₃₆ and resistor R ₃₆ forms a low pass filter, the overlap of the two assemblies being low pass. Will result in a pass filter. When the present invention is employed in a linear compressor 10 ', it may be chosen to construct such filters that remove frequencies higher than 500 Hz and frequencies lower than 5 Hz from the signal read by the sensing assembly 11. As such, the output of the second filter circuit 42 will correspond to the piston displacement.

The signals read by the sensing assembly 11 and processed by the first filter circuit 40 and the second filter circuit 42 are transmitted to the electronic controller 16 and operated to prevent piston impact. something to do.

The signal processed by the first filter circuit 40 can be fed directly to the electronic controller 16 since the latter can be interpreted in a binary manner. This can be observed in FIG. 7 where the signal of the sensing assembly 11 signals that when the piston passes the maximum stroke point an impact may occur or is imminent and its displacement stroke should be reduced.

The signal processed by the second filter circuit 42 has various amplitudes because it corresponds to the piston displacement in the cylinder. In this way, the signal must pass through comparator 45 before being passed to the electronic controller 16. The comparator 45 is connected to a reference voltage that must be adjusted according to the characteristics of the fluid pump 10. Alternatively, an A / D converter may be used instead of the comparator 45.

As can be seen in FIG. 7, once the sensing assembly 11 detects the maximum stroke value, this situation must be signaled to the electronic controller 16.

For example, to implement the sensing assembly by using a piezoelectric (PZT or piezoelectric) sensor, high frequency (greater than 5 kHz) components occur when the piston collides with each stroke end, and the first filter circuit 40 Should only select these high frequency components of the signal generated by the sensing assembly 11 since they identify the mechanical impact of the piston with the cylinder top or stroke end. On the other hand, the second filter circuit 42 must be adjusted to select the operating frequency (50 or 60 Hz) of the system and to remove the DC or high frequency components, since the information of the stroke will be within the operating frequency. to be. Apparently, the technique related to the present example of the piezoelectric sensor should not be taken as a limiting element to the presentation of the present invention, in which other types of sensors may be used to implement the sensing assembly 11, for example This is because other types of filters may exist.

By using two sensors:

According to this variant, it may be selected to provide a fluid pump 10 with two sensors having different functions: impact sensor 35, which provides a signal to be interpreted by the electronic controller 16. And a piston position sensor.

In this embodiment, the signal processing module 31 will receive a signal from each of the sensors 35, 36, as shown in FIG. 3A, one to convey the information to the electronic controller 16. Proceed in the same manner as described in the case of using a sensor.

Although one of the methods of interpreting the signal read by the position sensor is described in patent document BR9907432-0, other forms of monitoring may be used.

Type of sensor and each arrangement in fluid pump 10:

As the impact sensor, an accelerometer type sensor as already mentioned above can be used, for example. In this case, the impact sensor 35 should be connected to the cylinder of the fluid pump 10 and preferably secure such accelerometer with the cylinder of the fluid pump 10 so that a piston impact can be detected. You must do it.

The position sensor 36 may be implemented by, for example, a magnetic sensor. Sensors of this type emit a magnetic field obstructed by the piston's approach to generate a wave measurable by the electronic controller 16. The position sensor 36 may be arranged, for example, in a cylinder of the fluid pump.

How to Control the Fluid Pump (10)

In order to drive the fluid pump 10 and the system for controlling the linear compressor, or the cooler which may constitute a refrigerator or an air conditioning system, the following steps shown in FIG. 8 must be performed.

Each time the fluid pump 10 receives a trigger signal or every time the fluid pump starts up, it causes a piston displacement in the cylinder with minimal stroke, as described above, and continuously By increasing the size, the fluid pump 10 must be started.

The piston stroke should then be monitored to detect possible impacts, and if no impacts occur, the stabilization time is set to conclude that the system has stabilized, i.e. to determine whether no impacts will occur during this period. Should be given.

With regard to the term "impact", it should be considered that the "impact" may be an impact on the impact of the piston, as it will depend on the type of sensor used to monitor such steps. In the case of the use of an accelerometer type sensor, the piston impact with the stroke end would correspond to a collision. On the other hand, as described, for example, in documents BR0001404-4 and BR0200898-0, when contact sensors are used, or even in the case of magnetic sensors, in the context of impact, the actual collision of the piston with each stroke end. There will be no, but there will only be an impending impact as described above.

After the step of stabilization time, if the system is stabilized, that is, no impact occurs during the stabilization time, the piston stroke must be increased again and this routine must be repeated until an impact is detected.

The value of the stabilization time will depend on the type of fluid pump to be used. For use in linear compressors, this settling time will be on the order of a few seconds to a few minutes, typical values of tens of seconds. The exact designation of the magnitude of the value of the stabilization time can be determined as a monitoring function of the piston stroke. Thus, a stabilization time of the size determined by the piston stroke to be monitored by the external system can be applied. The increase in displacement magnitude is valid when it is certain that the piston stroke can be monitored and no further impact will occur.

In the next step, after detection of the impact, the piston stroke has to be reduced and the maximum value of the piston stroke at the fluid pump 10 is set. After this step, when the pump must be started with a minimum stroke, as described above, under the condition that no electrical or mechanical error occurs, the fluid pump 10 is driven in a constant manner.

When reducing the displacement stroke, the maximum value of the piston displacement must be stored in the electronic controller 16 to ensure that the piston will move by a safe and appropriate displacement as long as the efficiency of the compressor is taken into account. In other words, start the monitoring of the piston stroke with the maximum value of the displacement obtained from the impact. It may be selected to reduce the magnitude of the piston displacement, for example in percentage.

As such, once the maximum value of piston displacement is known, the electronic controller 16 will not allow the fluid pump to operate above the limit, and even if further impact occurs, the electronic controller ( 16) must recalibrate the system, ie increase the piston displacement continuously, starting at the minimum stroke. In order to make this possible, the system must be in operation at all times as well as during the weighing routine.

As mentioned above, the step of starting the fluid pump 10 with a minimum stroke can be performed periodically, and in this way, the fluid pump 10 can be continuously metered to the maximum piston stroke.

Linear To the compressor  Applications:

As mentioned above, the control system for controlling the fluid pump 10 as well as the respective control method is especially for applications involving a linear compressor 10 ', which is positioned reversibly in the cylinder. It is because it has a piston, and the cylinder has a piston displacement stroke, and has a stroke end.

The application in this case is particularly useful because the piston vibrates freely in the cylinder and the tolerances in the assembling step must be adjusted.

The advantages of the present invention are that the tolerance of electrical and mechanical components can be greater because the metering of the fluid pump 10 is foreseen every time the equipment is turned on. In this way, the metering step during assembly and manufacture of the fluid pump 10 can be eliminated, resulting in time gains and consequently financial benefits.

The possibility of automatic adjustment each time an error is detected also results in a more stable fluid pump 10 when compared to those assembled according to the prior art.

In addition, it is possible to use less accurate sensors or sensors with reduced gain and offset as the metering of the system is foreseen.

Optimization of the efficiency of the fluid pump 10 is important because the piston can operate close to the stroke end, resulting in maximum efficiency.

The possibility of using one sensor to simultaneously monitor the displacement of the piston and the impact is also an economical benefit, as it eliminates the need for inserting one or more sensors on the fluid pump 10 as well as saving parts. to be. In addition, integration with other piston-shifting systems is also possible.

Preferred embodiments have been described so far, and it should be understood that the scope of the present invention is limited only by the content of the appended claims, including other possible variations and including possible equivalents.

Claims (31)

A fluid pump control system, Wherein the fluid pump 10 includes a piston removably positioned within the cylinder, the cylinder having a piston displacement stroke, the cylinder having a stroke end, The fluid pump 10 is driven by a powered electric motor, the system includes an electronic controller 16 for controlling the voltage, The system is A sensing assembly 11 for measuring movement of the piston, and The electronic controller 16 electrically connected to the sensing assembly 11, The electronic controller 16 is arranged to monitor the displacement of the piston in the cylinder by detecting an impact signal, the impact signal being transmitted by the sensing assembly 11 upon occurrence of an impact with the stroke end of the piston. The impact signal is transmitted to the electronic controller 16 by the sensing assembly 11, The electronic controller 16 is configured to continuously increase the piston displacement stroke by increasing the voltage supplied to the electric motor, the voltage increase being the maximum value of the piston displacement corresponding to the piston displacement by the stroke end. And a trigger signal until the occurrence of the impact to store the fluid pump control system. The method of claim 1, Said maximum value of piston displacement corresponds to a displacement of the maximum efficiency of said fluid pump (10). 3. The method of claim 2, The trigger signal is characterized in that generated by the electronic controller (16) in the event of a problem with the fluid pump (10). The method according to claim 1 or 3, Fluid pump control system, characterized in that the fluid pump (10) is driven with a minimum piston displacement stroke. The method of claim 3, The fluid pump control system, characterized in that is driven when the trigger signal is generated. The method of claim 5, A first filter circuit 40 electrically connected to the electronic controller 16, The first filter circuit 40 is of a high pass type for cutting frequencies below 5 KHz, the impact signal read by the sensing assembly 11 is filtered by the first filter circuit 40, and the electronic controller. Fluid pump control system, characterized in that it is supplied to (16). The method of claim 6, The sensing assembly (11) comprises an impact sensor (35) connected to the cylinder of the fluid pump (10). The method of claim 7, wherein The impact sensor (35) is a fluid pump control system, characterized in that it comprises an accelerometer fixed with the cylinder of the fluid pump (10). The method of claim 5, The sensing assembly (11) has a position sensor (36) of a piston displacement stroke, the position sensor (36) being electrically connected to the electronic controller (16). 5. The method of claim 4, The sensing assembly 11 comprises a second filter circuit 42 electrically connected to the electronic controller 16, the second filter circuit 42 being of a low pass type for cutting frequencies higher than 500 Hz, The signal read by the sensing assembly 11 is filtered by the second filter circuit 42 and supplied to the electronic controller 16, the read signal is filtered by the second filter circuit 42, and the cylinder A fluid pump control system, characterized in that it corresponds to a signal of piston displacement within. The method of claim 10, A signal of piston displacement in the cylinder is transmitted to the electronic controller (16), wherein the electronic controller (16) prevents piston displacement by the stroke end. As a fluid pump 10 control system, The fluid pump 10 includes a piston removably positioned in a cylinder, the cylinder having a piston displacement stroke, the cylinder having a stroke end, The fluid pump 10 is driven by a powered electric motor, The system is: Piston-position sensing assembly (11) and An electronic controller 16 electrically connected to the sensing assembly 11, The electronic controller 16 monitors the piston displacement in the cylinder by detecting an impact signal, the impact signal being transmitted by the sensing assembly 11 in the event of a collision with the stroke end of the piston, the impact signal being Is delivered to the electronic controller 16 by the sensing assembly 11, The electronic controller 16 continuously increases the piston displacement stroke from the trigger signal until the occurrence of the impact to store the maximum value of the piston displacement, monitors the piston displacement in the cylinder, and prevents displacement by the maximum value of the piston displacement. Fluid pump control system, characterized in that. The method of claim 12, The electronic controller (16) is characterized in that it prevents piston displacement by the stroke end by reducing the level of voltage applied to the motor. 14. The method of claim 13, A first filter circuit 40 electrically connected to the electronic controller 16, the first filter circuit being of a high pass type for cutting frequencies below 5 KHz, the impact read by the sensing assembly 11; The signal is filtered by the first filter circuit (40) and fed to the electronic controller (16). The method of claim 14, The sensing assembly (11) comprises an accelerometer fixed close to the cylinder of the fluid pump (10), wherein the impact signal is generated by the accelerometer. 14. The method of claim 13, The sensing assembly (11) comprises a position sensor (36) for sensing piston displacement, the position sensor being electrically connected to the electronic controller (16). 14. The method of claim 13, The sensing assembly 11 includes a second filter circuit 42 electrically connected to the electronic controller 16, the second filter circuit 42 being of a low pass type for cutting frequencies higher than 500 Hz, The signal read by the sensing assembly 11 is filtered by the second filter circuit 42, supplied to the electronic controller 16, and the read signal is filtered by the second filter circuit 42. And a signal of piston displacement in the cylinder. As a fluid pump control method, The fluid pump 10 includes a piston removably positioned in the cylinder, The cylinder has a piston displacement stroke, The cylinder has a stroke end, The method is: (a) monitoring the piston stroke in the cylinder to detect impact with the stroke end; (b) monitoring the piston stroke during the stabilization time, and   (i) if no impact occurs during the stabilization time, increasing the piston stroke and repeating step (b), or   (ii) if the impact occurs during the stabilization time, reducing the piston stroke. 19. The method of claim 18, Prior to step (a), the step of increasing the piston stroke is foreseen. 20. The method of claim 19, Before the step of increasing the piston stroke, the fluid pump (10) is started with a minimum piston displacement stroke. 21. The method of claim 20, Starting the fluid pump (10) with a minimum piston displacement stroke is performed at the start of operation of the fluid pump (10). 22. The method of claim 21, Starting the fluid pump (10) is performed periodically. 23. The method of claim 22, Starting the fluid pump (10) is carried out when an error occurs. The method according to any one of claims 18 to 23, After said step (ii), said piston stroke operates constantly. 25. The method of claim 24, After the step of constantly operating the stroke, the storage of the maximum value of the piston displacement in the electronic controller (16) is foreseen. 25. The method of claim 24, After the step of constantly operating said stroke, said piston stroke is monitored. As a fluid pump control method, The fluid pump 10 includes a piston removably positioned in the cylinder, The cylinder has a piston displacement stroke, The cylinder has a stroke end, This method, (a) turning on the fluid pump 10 causing the piston to move in the cylinder, (b) continuously increasing the piston stroke to such an extent that an impact with the stroke end occurs, (c) monitoring the piston stroke for a stabilization time between successive increases in the stroke, and (d) if the impact occurs during the stabilization time, reducing the piston stroke. 28. The method of claim 27, In said step (a), the piston stroke of said fluid pump (10) starts with a minimum displacement stroke. The method of claim 28, After step (d), the monitoring of the piston displacement is foreseen. A linear compressor comprising a piston repositionably positioned in a cylinder, The cylinder has a piston displacement stroke, the cylinder has a stroke end, The linear compressor, Piston-position sensing assembly (11) and An electronic controller 16 connected to the sensing assembly 11, The electronic controller 16 monitors the piston displacement in the cylinder by detecting an impact signal, the impact signal being transmitted by the sensing assembly 11 upon occurrence of an impact with the stroke end of the piston, The impact signal is transmitted to the electronic controller 16 by the sensing assembly 11, The electronic controller (16) is characterized in that it continuously increases the piston displacement stroke by the degree of impact to store the maximum value of the piston displacement. An ambient cooler comprising a control system as defined in claim 1.

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